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Environmental impact assessments for new Arctic infrastructure do not adequately consider the likely long-term cumulative effects of climate change and infrastructure to landforms and vegetation in areas with ice-rich permafrost, due in part to lack of long-term environmental studies that monitor changes after the infrastructure is built. This case study examines long-term (1949–2020) climate- and road-related changes in a network of ice-wedge polygons, Prudhoe Bay Oilfield, Alaska. We studied four trajectories of change along a heavily traveled road and a relatively remote site. During 20 years prior to the oilfield development, the climate and landscapes changed very little. During 50 years after development, climate-related changes included increased numbers of thermokarst ponds, changes to ice-wedge-polygon morphology, snow distribution, thaw depths, dominant vegetation types, and shrub abundance. Road dust strongly affected plant-community structure and composition, particularly small forbs, mosses, and lichens. Flooding increased permafrost degradation, polygon center-trough elevation contrasts, and vegetation productivity. It was not possible to isolate infrastructure impacts from climate impacts, but the combined datasets provide unique insights into the rate and extent of ecological disturbances associated with infrastructure-affected landscapes under decades of climate warming. We conclude with recommendations for future cumulative impact assessments in areas with ice-rich permafrost.
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70-year retrospective of remote sensing applied to cumulative impact assessments, Prudhoe Bay Oilfield, Alaska
Cumulative impact assessments (CIAs) for new Arctic oilfields have not adequately addressed the potential landscape impacts of climate change or the indirect impacts of infrastructure in areas with ice-rich permafrost (IRP) (e.g., Raynolds et al. 2020). The main goals of this paper are: (1) trace the history of remote sensing for assessing past cumulative impacts in the Prudhoe Bay Oilfield (PBO), Alaska; (2) discuss some promising new remote-sensing and modeling tools; and (3) point toward improved capability to predict future changes. We first define IRP and cumulative impacts (CIs) and distinguish direct impacts (footprint) of infrastructure from the indirect impacts that follow construction. Aerial photographs (U.S. Navy 1948–1949) provided images of PBO landscapes before development occurred. The oil industry initiated annual high-resolution aerial-photograph missions of the PBO in 1968. In the same year, the International Biological Program (IBP) Tundra Biome started geoecological investigations that used these images to map landforms, soils, and vegetation of the PBO (Walker et al. 1980). The maps were later adapted to GIS approaches in three highly impacted 25-km2 areas of the PBO, which included several years of changes to tundra areas adjacent to infrastructure (Walker et al. 1987). The National Research Council later updated these three landscape-scale maps to 2001 and contracted the oil companies and Quantum Spatial Inc. to produce a regional-scale historical analysis of the network of roads, pipelines and other forms of infrastructure in all the North Slope Oilfields (NRC 2003). The regional- and landscape-scale maps used for NRC analysis were updated again in 2010 when unexpected rapid expansion of ice-wedge thermokarst was detected (Raynolds et al. 2014, 2016). Up to this time, CIAs of the PBO relied on aerial photographs and maps produced by the oil industry. The spatial resolution of available satellite-based remote-sensing data was insufficient to discern the details of periglacial landforms (e.g., ice-wedge polygons and nonsorted circles) or of roads, pipelines, or changes to land surfaces adjacent to infrastructure. Industry-sponsored studies that used remote-sensing products included studies of oil-pipeline spills, reserve-pits leaks (e.g., Jorgenson et al. 1995), off-road vehicles trails, and recovery following removal of gravel pads. Highlighted studies for this talk include a new NSF project that is part of the NSF Navigating the New Arctic initiative that is using integrated ground-based studies, advanced remote-sensing tools, and improved modeling approaches to examine climate- and infrastructure-related changes (Walker et al. 2022, Bergstedt 2022). Other projects that use PBO datasets for calibration, include an analysis of long-term impacts from a catastrophic flood (Shur et al. 2016, Zwieback et al. 2021) and studies that are using massive amounts of high-resolution imagery and pattern-recognition tools to detect and map ice-wedge polygons, water bodies, and infrastructure across the circumpolar Arctic (Bartsch et al. 2020; Witherrana et al. 2021). These tools combined with improved modeling approaches that bridge the gap between regional and engineering scales (e.g., Deimling et al. 2021) promise to greatly improve our ability to predict and monitor future infrastructure and landscape changes in areas with IRP.
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- Award ID(s):
- 1928237
- PAR ID:
- 10537684
- Publisher / Repository:
- NSF PAR
- Date Published:
- Subject(s) / Keyword(s):
- Cumulative impact assessment Arctic oilfields climate change infrastructure ice-rich permafrost remote sensing Prudhoe Bay Oilfield modeling aerial photographs GIS ice-wedge thermokarst circumpolar Arctic
- Format(s):
- Medium: X
- Location:
- Fairbanks, Alaska
- Sponsoring Org:
- National Science Foundation
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